En:HOWTO: Finding right network kernel driver

To find out which modules you must use..
the most simple thing to do is cat log file and grep for eth entry's ..
This will work if your Sabayon linux have already recognized your ethernet card (most cases).
In this example we look for eth0 and eth1 entry's, so if you have more cards just put at the end
eth[0,1,2,3,n] n = last ethernet card.

If you do have multiple ethernet cards, good practice is to put aliases into
/etc/modules.d/aliases ,so in this particular case it would look like

alias eth0 e100 alias eth1 via_rhine

This will prevent swapping eth0 and eth1 which occur because of some bugs in coldplug/udev, as
the first driver which get loaded becomes eth0, and we don't want that. We need to know exactly
which card is eth0 and eth1 to configure our network.